Firstly, why are you so angry?

the dog looks sad

No it doesn't.

The floor and walls are covered in filth

The floors are relatively clean for a garage. I know no garage I've ever owned had spotless floors.

The walls look a bit weathered and unfinished, but it's not "covered in filth". It's just showing its age, it's not layered in grime.

good enviorment for the dog to be living in

It just looks like a garage to me. We don't know the dog actually lives in there 24/7. There's no reason to assume that. I sometimes take photos of my dog in my building's parking lot (because I'm always taking photos of my dog and sometimes we happen to be in the parking lot). But that doesn't mean he lives there.

Lots of dogs enjoy cold hard surfaces when its a bit hot out. It helps them cool down. My dog and my roommate's dog frequently run to cold tiles to lie down, or concrete like in this picture.

The dog looks well groomed, has its nails trimmed, seems a healthy weight. It seems relatively well cared for. There's not enough information in this photo to draw the conclusion that the "dog looks sad".

I don't know that it isn't sad, but it at least looks like it has its basic needs taken care of, and isn't showing any outward signs of sadness (nor happiness either). It's mostly just a dog hanging out on the floor.

My dog looks just like that most of the time I look over at him.